Digital Private Network Signalling System: Difference between revisions

Revision as of 06:53, 26 June 2014

Revision as of 00:46, 10 July 2014

Line 13:

DPNSS was an active (and successful) collaboration between PBX manufacturers and BT which started relatively slowly (BT & Plessey) but quickly snowballed with [[Mitel|MITEL]], [[General Electric Company plc|GEC]], [[Ericsson]], [[Philips]] and eventually Nortel all joining to create a powerful and feature rich protocol.

BT and some of the UK manufacturers championed DPNSS into ECMA and CCITT (ITU) but it was eventually deprecated by the standards bodies in favour of Q931 and QSig. Nevertheless, the elegance of the protocol and its compatibility with PBX features ensured the adoption DPNSS actually grew in Europe, compared to the much slower take-up of Qsig.

There were also attempts (during 1984) to take DPNSS into North America. Unfortunately the structures for the creation of standards in North America seemed to prevent manufacturer collaboration as a route forward and the [[ANSI]] werestandards body was not interested in creating PBX interworking standards.

Version 1 of BTNR188 (DPNSS) was issued in 1983; the last version of DPNSS to be released 6 in 1995 included compatibility with ISDN features released in V5. A lightweight version of DPNSS 'APNSS' was developed using analogue trunks (Sometimes compressed) and a modem to support D channel signalling.